Monitoring camera and monitoring camera control method

ABSTRACT

An image signal processing DSP subjects an image captured by an imaging element having a zoom lens to image processing for identifying a tracking target. In accordance with zoom information generated by the image signal processing DSP, the main CPU controls the zoom lens and controls a turn table that moves the imaging element in panning and tilting directions in accordance with pan and tilt information, to track the tracking target. During tracking of the tracking target, a determination is made, from information about movements of the tracking target generated by the image signal processing DSP, as to whether or not the target to be tracked has intruded the inside of the area from the outside. In a case where the target has intruded the inside of a preset area from the outside, an alarm command is produced when the target continually remains in the area for; e.g., one second.

TECHNICAL FIELD

The present invention relates to a monitoring camera equipped with afunction of performing image processing for identifying a trackingtarget as well as to a monitoring camera control method.

BACKGROUND ART

Monitoring camera hitherto include monitoring cameras having a functionof generating an alarm by utilization of a difference among movements ofa subject captured by means of stationary camera that perform neitherpanning nor tilting and cameras having a function of generating an alarmwhen the motion of a subject is not oriented in a given direction.Further, some monitoring cameras have a function of generating an alarmwhen a subject has approached a prohibited area by combining imagescaptured by a plurality of stationary cameras that perform neitherpanning nor tilting. Patent Document 1 discloses that three-dimensionalcoordinates of a power transmission line, a steel tower, or a truckcrane are determined by processing images captured by a plurality ofstationary cameras; that a dangerous area is set around the powertransmission line; and that, when the truck crane enters the dangerousarea, an alarm is produced by monitoring a location of the truck crane.

Patent Document 1: JP-A-6-347220

DISCLOSURE OF THE INVENTION Problem that the Invention is to Solve

However, the related-art monitoring cameras encounter the followingdrawbacks.

(1) When an alarm is produced by utilization of a difference amongmovements of a subject, the camera is effective for monitoring animaging site that is free of motion or where there are small movements.However, when the camera is used for monitoring an imaging site wherethere are many movements, erroneous alarms are frequently produced;therefore, the camera is not usable. As mentioned above, depending on amonitored site, an increase in the number of times an alarm is producedis not preferable for a supervisor who is performing monitoringoperation in terms of working efficiency. Conceivable imaging siteswhere there occur many movements include; for instance, a site wherethere is reflection from a road surface, a site where swaying actions ofwood occur, a site where blinking of a computer display (monitor)occurs, a site where flickering of a fluorescent lamp occurs, and thelike.

(2) In a case where images of a plurality of stationary cameras arecombined together and when an alarm is produced in response to entry ofa subject into a prohibited area, if a motion difference stemming fromvideos exists in the camera monitoring the area, an alarm will beproduced even when a subject has not entered the area from the outside.FIG. 5 shows a case where two stationary cameras are installed. In anillustrated example, an area monitored by a camera 100 is taken as “A,”and an area monitored by a camera 110 is taken as “B” (a relationship ofmagnitude is A>B). When a subject 120 enters the area B from the area A,an alarm is to be produced. However, even when the subject 120 is in thearea B from the beginning and subsequently makes a movement in the areaB, an alarm is produced. Namely, the areas A and B can freely be set;hence, if a subject (a person) is incidentally in the area B when thearea B is set, an alarm will be produced in response to movement of thesubject.

(3) Equipment that combines images with each other by use of a pluralityof stationary cameras (video combination equipment) is required, whichadds to the cost of a system. Moreover, it is impossible to accuratelydetect entry of a subject into an area from the outside unlesspositional information about respective stationary cameras is accuratelytransmitted to the image combination equipment. Specifically,high-precision installation of respective stationary cameras isrequired, and installation entails consumption of efforts and time.

The present invention has been conceived in light of the circumstanceand aims at providing a monitoring camera that does not produce an alarmeven when a subject makes a movement within a set area and that enablescurtailing of system cost, as well as providing a monitoring cameracontrol method.

Means for Solving the Problem

A monitoring camera of the present invention comprises: imaging meanshaving a zoom lens; a turn table that moves the imaging means in panningand tilting directions; image processing means that subjects an imagecaptured by the imaging means to image processing for identifying atracking target, to thus generate tracking information includinginformation about motion of the tracking target and pan, tilt, and zoominformation; tracking mans that tracks the tracking target bycontrolling the zoom lens of the imaging means in accordance with thezoom information generated by the image processing means and controllingthe turn table in accordance with the pan and tilt information generatedby the image processing means; and intrusion detection means thatdetermines, from information about motion of the tracking targetgenerated by the image processing means, whether or not the trackingtarget has intruded inside of a preset area from outside, during thecourse of tracking the tracking target, and that outputs an alarm onlywhen the tracking target has intruded the inside of the area from theoutside.

According to the configuration, only when the tracking target hasintruded the inside of the area from the outside, an alarm command isgenerated. Accordingly, no alarm command is produced even when there aremovements of a subject in the area (e.g., reflection from a roadsurface, swaying actions of wood, blinking of a computer display,flicking of a fluorescent lamp, and the like). Further, the monitoringcamera has imaging means having a zoom lens, a turn table for moving theimaging means in panning and tilting directions, and tracking means fortracking the tracking target. Therefore, precise adjustment of alocation where a camera is to be installed, which has been difficult fora related-art stationary camera, can be performed accurately, readily.Namely, the degree of freedom of the location where the camera is to beinstalled can be enhanced. A plurality of cameras are not used, nor isrequired video combination equipment. Hence, system cost can be helddown.

Further, in the monitoring camera of the present invention, in a casewhere the tracking target has intruded the inside of the area from theoutside, the intrusion detection means outputs an alarm when thetracking target continually stays in the area for a predetermined periodof time since the tracking target performed intrusion.

According to the configuration, influence of reflection from a roadsurface, swaying actions of wood, blinking of a computer display,flicking of a fluorescent lamp, and the like, can be eliminatedsubstantially, completely. Accuracy of an alarm output can be increased.

In the monitoring camera of the present invention, the intrusiondetection means does not output an alarm when tracking of the trackingtarget is started from the inside of the area and when the trackingtarget keeps moving in the area.

According to the configuration, even if a subject (a person) isincidentally located in an area when the area is set and when thesubject has made a movement, no alarm is output.

A monitoring camera system of the present invention has at least two ofany monitoring cameras, and tracks the tracking target in an associatedmanner by supplying an alarm signal from one camera directly to theother camera.

According to the configuration, at least two monitoring cameras operatein an associated manner; hence, the tracking target can be trackedwithout fail.

A monitoring camera control method of the present invention comprises:an image processing step of subjecting an image captured by imagingmeans having a zoom lens to image processing for identifying a trackingtarget, to thus generate tracking information including informationabout motion of the tracking target and pan, tilt, and zoom information;a tracking step of tracking the tracking target by controlling the zoomlens of the imaging means in accordance with the zoom informationgenerated in the image processing step and controlling the turn table,which moves the imaging means in panning and tilting directions, inaccordance with the pan and tilt information generated in the imageprocessing step; and an intrusion detection step of determining, fromthe information about motion of the tracking target generated in theimage processing step, whether or not the tracking target has intrudedinside of a preset area from outside, during the course of tracking thetracking target, and that outputs an alarm only when the tracking targethas intruded the inside of the area from the outside.

According to the method, only when the tracking target has intruded theinside of the area from the outside, an alarm command is generated.Accordingly, no alarm command is produced even when there are movementsof a subject in the area (e.g., reflection from a road surface, swayingactions of wood, blinking of a computer display, flicking of afluorescent lamp, and the like). Further, in a monitoring cameraincluding imaging means having a zoom lens and a turn table for movingthe imaging means in panning and tilting directions, the zoom of thecamera is controlled, and the turn table is controlled, to thus move thecamera in panning and tilting directions, thereby tracking the trackingtarget. Hence, precise adjustment of a location where a camera is to beinstalled, which has been difficult for a related-art stationary camera,can be performed accurately, readily. Namely, the degree of freedom ofthe location where the camera is to be installed can be enhanced. Aplurality of cameras are not used, nor is required video combinationequipment. Hence, system cost can be held down.

Advantage of the Invention

According to the present invention, only when the tracking target hasintruded the inside of the area from the outside, an alarm command isgenerated. Accordingly, no alarm command is produced even when there aremovements of a subject in the area. Further, since the monitoring cameraincludes imaging means having a zoom lens, a turn table for moving theimaging means in panning and tilting directions, and tracking means fortracking the tracking target, precise adjustment of a location where acamera is to be installed, which has been difficult for a related-artstationary camera, can be performed accurately, readily. Namely, thedegree of freedom of the location where the camera is to be installedcan be enhanced. A plurality of cameras are not used, nor is requiredvideo combination equipment. Hence, system cost can be held down.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a schematic configuration of amonitoring camera of an embodiment of the present invention.

FIGS. 2A to 2D are views for describing a difference between a casewhere the monitoring camera shown in FIG. 1 produces an alarm and a casewhere no alarm is produced.

FIG. 3 is a timing chart for describing operation of the monitoringcamera shown in FIG. 1.

FIG. 4 is a block diagram showing a schematic configuration of amonitoring camera system equipped with the plurality of monitoringcameras shown in FIG. 1.

FIG. 5 is a view for describing drawbacks in a related-art monitoringcamera.

DESCRIPTIONS OF THE REFERENCE NUMERALS

-   -   10, lOA, lOB MONITORING CAMERA    -   11 IMAGING ELEMENT    -   12 TURN TABLE    -   13 SERVO MICROCOMPUTER    -   14 COMMUNICATION MICROCOMPUTER    -   15 VIDEO SIGNAL PROCESSING DSP    -   16 IMAGE SIGNAL PROCESSING DSP    -   17, 20 PROGRAM MEMORY    -   18 IMAGE DATA STORAGE MEMORY    -   19 MAIN CPU    -   22 FEP    -   23 MEMORY    -   24 ZOOM LENS    -   25 ZOOM CONTROL UNIT    -   50 EXTERNAL DEVICE    -   60 RECORDER    -   70 MONITOR    -   80 BUILDING    -   90 CHARACTER    -   P TRACKING START POINT    -   C AREA    -   C1, C2 MONITORED AREA    -   C3 CORNER AREA

BEST MODE FOR IMPLEMENTING THE INVENTION

A preferred embodiment for implementing the present invention ishereunder described in detail by reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of amonitoring camera of an embodiment of the present invention. In thedrawing, a monitoring camera 10 of the present embodiment has an imagingelement 11 for imaging a subject, such as a CCD (Charge-Coupled Device)and a CMOS (Complementary Metal Oxide Semiconductor); a front-endprocessor (hereinafter abbreviated as FEP) 22 that processes imageinformation output from the imaging element 11 and converted intoelectric charges; a turn table 12 for orienting the imaging element 11in a panning direction and a tilting direction; a servo microcomputer 13that drives the turn table 12; a communication microcomputer 14 thatexchanges a command with an external device 50; a video signalprocessing DSP (Digital Signal Processor) 15 that processes processingincluding activation of an electronic shutter, and the like, in responseto a video signal from the FEP 22; an image signal processing DSP(Digital Signal Processor) 16 that identifies a tracking target bysubjecting a digital image signal output from the video signalprocessing DSP 15 to binarization processing, noise reductionprocessing, and others; program memory 17 that stores a program forcontrolling the video signal processing DSP 16; image data storagememory 18 that stores image data processed by the image signalprocessing DSP 16; a main CPU (Central Processing Unit) 19 that controlsindividual sections of the camera; program memory 20 that stores aprogram for controlling the main CPU 19; and memory 23 that stores panand tilt angle information and setting information about operations. Azoom lens 24 is attached to a front side of the imaging element 11, andthe main CPU 19 controls the zoom lens 24, such as a zoom-in action, byway of a zoom control unit 25.

The image signal processing DSP 16 corresponds to image processingmeans. The main CPU 19 corresponds to tracking means and intrusiondetection means. The zoom lens 24 and the imaging element 11 correspondto imaging means.

The imaging element 11 is mounted on the turn table 12, and thedirection of the imaging element 11 can also be changed by rotating theturn table 12, so that a subject which a user desires to see can bephotographed. The turn table 12 has a mechanism and a motor (omittedfrom the drawings) for moving the imaging element 11 in a panningdirection and a tilting direction and is controlled by the servomicrocomputer 13. Pan and tilt angle information is stored in the memory23 along with a position number. The main CPU 19 can automaticallyrotate the turn table 12 through the pan and tilt angles stored alongwith the position number, so long as the user inputs a position numberfrom a controller (not shown). The servo microcomputer 13 has a driverfor driving the motor of the turn table 12 and a microcomputer forcontrolling the driver in compliance with a command from the main CPU19. Nonvolatile memory, such as flash RAM (Random Access Memory), isused for the program memory 17 and 20. Volatile memory, such as RAM, isused for the image data storage memory 18.

The video signal processing DSP 15 processes a video signal from thecamera 11; outputs an analogue video signal produced from the videosignal; and outputs a digital image signal to the image signalprocessing DSP 16. The image signal processing DSP 16 captures thethus-delivered digital image signal every 100 ms, for instance, therebydetermining a difference. Thus, tracking information includinginformation about movements of the tracking target (a person) and pan,tilt, and zoom information is output as serial data to the main CPU 19.The image signal processing DSP 16 has three states; namely, a “waitstate,” a “search state,” and a “tracking state,” and notifies the mainCPU 19 of which one of the states is a current state. The “wait state”is a state in which an automatic tracking capability is deactivated, andthe “search state” is a state in which the automatic tracking capabilityis active and in which a moving subject is detected and in which pan,tilt, and zoom operations are controlled in such a way that the subjectcomes to the center, to thus determine whether or not the subject is aperson. The “tracking state” is a state in which, after the person hasbeen identified in the “search state,” the person is actually tracked.

The main CPU 19 captures the video signal output from the imagingelement 11 and transfers the thus-captured signal to the video signalprocessing DSP 15. The main CPU 19 also manages the position of an areaset by the user and the position of the tracking target specified by theimage signal processing DSP 16 by means of coordinates. When thetracking target is located by the image signal processing DSP 16, atracking start position (a tracking start point) is recorded, andtracking is commenced. At this time, in accordance with the pan and tiltinformation input from the image signal processing DSP 16, the main CPU19 controls the servo microcomputer 13; drives the turn table 12; andmoves the imaging element 11 in the pan and tilt directions. Further,the main CPU 19 controls zooming action of the imaging element 11 inaccordance with zoom information input by the image signal processingDSP 16.

The main CPU 19 also performs tracking operation in accordance withinformation about the motion of the tracking target input by the imagesignal processing DSP 16. Further, during the course of trackingoperation, the main CPU determines whether or not the tracking targethas intruded the inside of a preset area from the outside. When thetracking target has intruded the inside from the outside and when, forinstance, one second has elapsed after a tracking point has entered thearea, an alarm command is output. When the tracking start point remainsinside the area and when tracking operation is incessantly performedwithin the area, the main CPU 19 does not output an alarm command. Inaddition to being output as an alarm signal (a terminal alarm: L active)directly to the terminal from the main CPU 19, the alarm command can beoutput by way of the video signal processing DSP 15 or by way of thecommunication microcomputer 14.

A difference between operation of the main CPU 19 performed when analarm is produced and operation of the same performed when no alarm isproduced is now described by reference to FIGS. 2A to 2D. FIGS. 2A and2B show cases where no alarm is produced, and FIGS. 2C and 2D show caseswhere an alarm is produced. The case of FIG. 2A where no alarm isproduced is a case where a tracking start point P is situated within anarea C and where tracking operation is incessantly performed within thearea C. The case of FIG. 2B where no alarm is produced is a case wherethe tracking start point P is situated outside of the area C and wheretracking operation is incessantly performed outside of the area C. Thecase FIG. 2C where an alarm is produced is a case where the trackingstart point P is situated outside of the area C and where the trackingstart point P is situated outside of the area C and where a trackingtarget is now being tracked for; for example, one second, within thearea C after having intruded the area C from the outside. The case ofFIG. 2D where an alarm is produced is a case where the tracking startpoint P is situated within the area C and where the tracking target onceexits the area C, again intrudes the inside of the area C, and is nowbeing tracked for; e.g., one second, within the area C.

FIG. 3 is a timing chart showing the state of the image signalprocessing DSP 16 and operation of the main CPU 19. In the drawings, theimage signal processing DSP 16 repeatedly enters a wait state, a searchstate, and a tracking state. The main CPU 19 determines, from thetracking information from the image signal processing DSP 16, whether atracking target is situated outside or inside. When the target isdetermined to have intruded the area from the outside, an alarm commandis output only for four seconds after a wait of; for instance, onesecond. Specifically, the alarm command output is brought into an “L”active state only for four seconds.

As mentioned above, according to the monitoring camera 10 of the presentembodiment, the image signal processing DSP 16 subjects the imagecaptured by the imaging element 11 having the zoom lens 24 to imageprocessing for identifying the tracking target, and generates trackinginformation including information about movements of the tracking targetand pan, tilt, and zoom information. In accordance with the zoominformation generated by the image signal processing DSP 16, the mainCPU 19 controls the zoom function of the imaging element 11. Further, inaccordance with the pan and tilt information, the main CPU 19 controlsthe turn table 12 that moves the imaging element 11 in panning andtilting directions, thereby tracking the target. During the course oftracking the tracking target, the main CPU determines, from informationabout movements of the tracking target generated by the image signalprocessing DSP 16, whether or not the tracking target has intruded theinside of the preset area from the outside; and generates an alarmcommand when the target has intruded the area from the outside andcontinually stays in the area for one second. Namely, an alarm isproduced.

Therefore, only when the tracking target has intruded the inside of thearea from the outside, an alarm command is generated. Accordingly, noalarm command is produced even when there are movements of a subject inthe area (e.g., reflection from a road surface, swaying actions of wood,blinking of a computer display, flicking of a fluorescent lamp, and thelike). In particular, since a time lag; for instance, one second, from apoint in time when the tracking target intruded the inside of an areafrom the outside is set as conditions for generating an alarm command,influence of movements of the subject can be eliminated substantially,completely. Further, in a case where tracking is initiated from theinside of the area, even if the tracking target keeps moving within thearea, an alarm will not be produced. Therefore, even if a subject (aperson) is incidentally in an area at the time of setting of the area,an alarm command responsive to motion of the subject will not beproduced.

An alarm command is output when the tracking target has intruded thearea. Hence, erroneous generation of an alarm command, which wouldotherwise be caused by swaying action of wood, is not produced even whenwood is behind the set area, the degree of freedom of the location wherethe camera is installed can be enhanced. Since a plurality of camerasare not used and since video combination equipment is not required,system cost can be held down.

A monitoring camera system using the monitoring camera of the presentinvention will now be described. FIG. 4 is a block diagram showing aschematic configuration of the monitoring camera system of the presentembodiment. As shown in FIG. 4, the monitoring camera system of thepresent embodiment has two monitoring cameras lOA and lOB; a recorder 60that records video signals output from the respective monitoring cameraslOA and lOB; and a monitor 70 that displays a video recorded by therecorder 60. In the present embodiment, the monitoring camera lOA is seton one side surface of a building 80, and the monitoring camera lOB isset on the front of the building 80. An area monitored by the monitoringcamera lOA is Cl, and an area monitored by the monitoring camera lOB isC2. In relation to the monitoring camera lOA, a corner area C3 of thebuilding 80 is set as an alarm signal output area.

In the monitoring cameras lOA and lOB, when the tracking target isdetermined to have intruded the inside of the area from the outside asmentioned above, the main CPUs 19 output an alarm signal (a terminalalarm) directly to a terminal. The main CPUs 19 of the respectivemonitoring cameras lOA and lOB are arranged so as to be able to capturesignals from the respective alarm terminals. Data are set in the memory23 connected to the main CPUs 19 in such a way that, when signals areinput to the alarm terminals of the respective main CPUs 19, the mainCPUs 19 drive the respective turn tables 12 to panning and tiltingangles corresponding to certain preset position numbers so as to enter a“search state.” For instance, as shown in FIG. 4, the corner area C3 ofthe building 80 is set as an alarm signal output area in the monitoringcamera lOA.

Meanwhile, the same corner area C3 is previously set as a presetposition [1] in the monitoring camera lOB. When a signal is input to thealarm terminal, setting is made in such a way that the monitoring cameralOB is oriented to the preset position [1], to thus enter a “searchstate.” The monitoring camera lOA is connected to the alarm terminal ofthe monitoring camera lOB in such a way that the alarm signal outputfrom the monitoring camera lOA is input to the alarm terminal of themonitoring camera 10B.

As a result of the monitoring cameras lOA and lOB being set as mentionedabove, when a person 90 tracked by the monitoring camera lOA hasintruded the corner area C3 of the building 80, the main CPU 19 of themonitoring camera lOA outputs a terminal alarm, and the thus-outputsignal is input to the alarm terminal of the monitoring camera 10B. As aresult of the alarm signal being input to the monitoring camera lOB, themonitoring camera lOB is oriented toward the preset position [1], tothus enter a “search state,” identify the person 90 intruded the cornerarea C3 of the building 80, and track the person 90.

As mentioned above, the plurality of monitoring cameras 10 arepreviously set so as to perform associated operation, whereby thecameras can readily, automatically perform tracking operation. Inparticular, the monitoring cameras lOA and lOB located within a shortrange where they can capture the same area directly transmit signalswithout involvement of another equipment. Hence, the monitoring cameraslOA and lOB can quickly operate in an associated manner without regardto a situation, such as congestion of a network, a distant locationwhere another equipment is installed, and the like. Tracking can beperformed without losing the person 90.

Although the present invention has been described in detail and byreference to the specific embodiment, it is manifest to those skilled inthe art that the present invention is susceptible to various alterationsor modifications without departing the spirit and scope of the presentinvention.

The present patent application is based on Japanese Patent Application(JP-A-2007-033786) filed on Feb. 14, 2007, contents of which areincorporated herein for reference.

INDUSTRIAL APPLICABILITY

The present invention yields an advantage of not producing an alarm evenwhen a subject has made a movement within a set area and being able tohold down system cost, and can be applied to a monitoring camera system,and the like.

1. A monitoring camera comprising: an imager having a lens; an imageprocessor which identifies a tracking target in an image captured by theimager and generates tracking information; a main processor which tracksthe tracking target in accordance with the tracking informationgenerated by the image processor; and the main processor whichdetermines, based on the tracking information generated by the imageprocessor, whether or not the tracking target intrudes inside of apreset area from outside, and outputs an alarm only if the trackingtarget intrudes the inside of the preset area from the outside, wherein,if tracking of the tracking target starts from the inside of the presetarea and the tracking target remains in the preset area, the mainprocessor does not output the alarm, and wherein, if tracking of thetracking target starts from the inside of the preset area and thetracking target moves to the outside of the preset area, the mainprocessor does not output the alarm.
 2. A monitoring camera systemcomprising at least two monitoring cameras according to claim 1, whereinthe tracking target is tracked in an associated manner by supporting analarm signal from one camera directly to the other camera.
 3. Amonitoring camera according to claim 1, wherein the main processortracks the tracking target so that the tracking target is positioned ata center of the image captured by the imager.
 4. A monitoring cameracontrol method comprising: identifying a tracking target in an imagecaptured by an imager having a lens and generates tracking information;tracking the tracking target in accordance with the tracking informationgenerated; and determining, based on the tracking information generated,whether or not the tracking target intrudes inside of a preset area fromoutside, and outputting an alarm only if the tracking target hasintruded the inside of the preset area from the outside, wherein, iftracking of the tracking target starts from the inside of the presetarea and the tracking target remains in the preset area, the alarm isnot outputted, and wherein, if tracking of the tracking target startsfrom the inside of the preset area and the tracking target moves to theoutside of the preset area, the alarm is not outputted.
 5. A monitoringcamera comprising: an imager having a lens; an image processor whichidentifies a tracking target in an image captured by the imager andgenerates tracking information; a main processor which tracks thetracking target in accordance with the tracking information generated bythe image processor; and the main processor which determines, based onthe tracking information generated by the image processor, whether ornot the tracking target intrudes inside of a preset area from outside,and outputs an alarm if the tracking target intrudes the inside of thepreset area from the outside, wherein, if tracking of the trackingtarget starts from the inside of the preset area and the tracking targetremains in the preset area, the main processor does not output thealarm, wherein, if tracking of the tracking target starts from theoutside of the preset area and the tracking target remains the outsideof the preset area, the main processor does not output the alarm, andwherein, if tracking of the tracking target starts from the inside ofthe preset area and the tracking target moves to the outside of thepreset area, the main processor does not output the alarm.